The men's 400 metre individual medley event at the 2025 World Aquatics Championships was held on 3 August 2025 at the World Aquatics Championships Arena at the Singapore Sports Hub in Kallang, Singapore.

Background France’s Léon Marchand, the two-time defending World Champion and Olympic gold medalist, enters as the favorite, having posted a world-leading 4:07.11 earlier in 2025 despite injuries. Japan continues its strong tradition in the event, with Tomoyuki Matsushita, who swam 4:08.62 for silver at the Paris Olympics and improved to 4:08.61 this year, and Asaki Nishikawa, who recently recorded 4:09.63. The United States will be represented by Carson Foster, a two-time World silver medalist whose 4:07.92 ranks second among entrants, and Rex Maurer, who broke 4:10 for the first time in 2025. Great Britain’s Max Litchfield, New Zealand’s Lewis Clareburt, and Italy’s Alberto Razzetti are among the experienced medal contenders, while Russia’s Ilya Borodin, competing for the Neutral Athletes B team, and China’s Wang Shun could also challenge for the final.

Qualification Each National Federation was permitted to enter a maximum of two qualified athletes in each individual event, but they could do so only if both of them had attained the "A" standard qualification time. For this event, the "A" standard qualification time was 4:17.48. Federations could enter one athlete into the event if they met the "B" standard qualification time. For this event, the "B" standard qualification time was 4:26.49. Athletes could also enter the event if they had met an "A" or "B" standard in a different event and their Federation had not entered anyone else. Additional considerations applied to Federations who had few swimmers enter through the standard qualification times. Federations in this category could at least enter two men and two women to the competition, all of whom could enter into up to two events. +Top 10 fastest qualification timesSwimmerCountryTimeCompetitionLéon Marchand4:02.952024 Summer OlympicsBobby Finke4:07.462025 United States ChampionshipsCarson Foster4:07.642024 United States Olympic TrialsTomoyuki Matsushita4:08.612025 Japanese ChampionshipsMax Litchfield4:08.852024 Summer OlympicsAlberto Razzetti4:09.382024 Summer OlympicsChase Kalisz4:09.392024 United States Olympic TrialsAsaki Nishikawa4:09.632025 Japanese ChampionshipsRex Maurer4:09.652025 National ChampionshipsDaiya Seto4:09.682024 Sette Colli

Records Prior to the competition, the existing world and championship records were as follows.

Heats The heats were started at 10:02.

RankHeatLaneSwimmerNationTimeNotes 1 4 5 Tomoyuki Matsushita 4:10.39 Q 2 3 3 Asaki Nishikawa 4:10.41 Q 3 3 7 Ilia Borodin Neutral Athletes B 4:10.63 Q 4 3 5 Max Litchfield 4:11.41 Q 5 3 9 Maxim Stupin Neutral Athletes B 4:11.53 Q 6 3 6 Brendon Smith 4:13.08 Q 7 4 4 Léon Marchand 4:13.19 Q 8 4 8 Gábor Zombori 4:13.59 Q 9 4 1 Balázs Holló 4:13.88 10 4 2 Lewis Clareburt 4:13.89 11 2 5 Thomas Jansen 4:14.19 12 4 3 Alberto Razzetti 4:14.52 13 3 0 Zhang Zhanshuo 4:15.86 14 4 9 Lorne Wigginton 4:16.61 15 2 2 Daniil Giourtzidis 4:16.62 16 4 0 William Petric 4:16.91 17 2 7 Marius Toscan 4:17.01 18 2 1 Noah Zemansky 4:18.89 19 3 1 Cedric Büssing 4:18.95 20 4 6 Rex Maurer 4:19.30 21 2 9 Richard Nagy 4:19.69 22 2 6 Stephan Steverink 4:20.71 23 2 4 Jakub Bursa 4:22.28 24 1 5 Munzer Kabbara 4:23.51 NR 25 1 2 Nguyễn Quang Thuấn 4:23.99 26 1 6 Zackery Tay 4:26.71 27 1 4 Mohamed-Yassine Ben Abbes 4:29.14 28 1 3 Shoan Ganguly 4:30.40 29 1 7 Tan Khai Xin 4:30.90 30 4 7 Apostolos Papastamos 4:31.05 31 1 1 Ahmed Theibich 4:56.83 32 1 8 Mohamed Rihan Shiham 5:15.03 2 3 Kim Min-seop 2 0 Jaouad Syoud 2 8 Matthew Sates 3 2 Wang Shun 3 4 Carson Foster 3 8 Tristan Jankovics

Final The final took place at 19:59.

Rank Lane Name Nationality Time Notes 1 Léon Marchand 4:04.73 4 Tomoyuki Matsushita 4:08.32 3 Ilia Borodin Neutral Athletes B 4:09.16 4 5 Asaki Nishikawa 4:10.21 5 2 Maxim Stupin Neutral Athletes B 4:12.46 6 8 Gábor Zombori 4:12.51 7 6 Max Litchfield 4:12.77 8 7 Brendon Smith 4:13.28

References